A putty knife is a flat, flexible tool used primarily for applying and smoothing materials like putty or spackle. It typically has a metal blade and a comfortable handle, making it easy to maneuver in tight spaces. Putty knives come in various sizes, allowing users to choose the right one for their specific task. In addition to its primary use in home improvement and construction, a putty knife can also be handy for scraping surfaces, removing paint, or even spreading adhesives. Its versatility makes it a common tool in both professional and DIY projects.